It's the most sensitive spectra of human hearing BUT most designers appear to choose it for their mid-high pass. Why is this? It would seem to me that in an ideal world, a three way with a midrange driver covering 400-4khz would be the solution used most often but I more often still see three ways crossed to a tweeter lower......sometimes much lower.

Crossing from midrange to tweeter at 4kHz would require a small (3" or less) midrange speaker in order to maintain a smooth power response. A 5" midrange would beam way too much to cross that high, while a typical dome tweeter would not beam at all when it takes over. This mismatch in directivity causes the power response to droop in the midrange and then suddenly jump up when the tweeter takes over. Also the center to center spacing of the midrange and tweeter would be too large, compared to the wavelength of sound at 4kHz.

It's the most sensitive spectra of human hearing BUT most designers appear to choose it for their mid-high pass. Why is this? It would seem to me that in an ideal world, a three way with a midrange driver covering 400-4khz would be the solution used most often but I more often still see three ways crossed to a tweeter lower......sometimes much lower.

In an ideal world that would be the case but there is no such midrange driver so we are using what looks like the least compromise possible.

It's the most sensitive spectra of human hearing BUT most designers appear to choose it for their mid-high pass. Why is this? It would seem to me that in an ideal world, a three way with a midrange driver covering 400-4khz would be the solution used most often but I more often still see three ways crossed to a tweeter lower......sometimes much lower.

I mostly agree, but I would claim the range is more like 700 - 7000. I avoid crossovers in that range, although right at the lower edge is usually the only option.

In an ideal world that would be the case but there is no such midrange driver so we are using what looks like the least compromise possible.

But is it the best compromise?.....

One one hand we have a slight discontinuity in directivity and power response and on the other, we have shifting phase and overlapp. From a voicing standpoint, I'm no longer sure I've been choosing correctly.

I can get pretty close C to C spacing and directivity match with something like the SS 10F......and even if I need power power handling, a vertical pair which would introduce two lobes at +/- 20 degrees.......instead of bouncing more energy off of the floor and ceiling. Sounds like a good compromise.

I mostly agree, but I would claim the range is more like 700 - 7000. I avoid crossovers in that range, although right at the lower edge is usually the only option.

I've read your viewpoints on this extensively which has led me to where I am now in my thinking. Get that XO down to 1khz or less and the system just becomes something different......special IMO.

Now if like to pick your knowledge at some point as to why a 1.4-2" CD 2waveguide with a super tweeter isn't a trade you're willing to make. Is it the size of the horn?......the anomolies of a 2nd HF device and the associated combing?

This new crop of 2-3" 'mid woofers' with very low HD, not so bad power handling and efficiency are giving me reason for pause whenever I contemplate a design that's looking to do something different from what we've been doing. I look at commercial designs like ANYA and see a changing of the rules when we apply our current and past thinking.

Obviously, I'm talking about line source systems to a degree. The current thoughts for home use......too big, too expensive, needs eQ.....and on and on. But I pose WHY do they have to be floor to ceiling? Who actually sits below or above a vertical axis of 20 degrees at home? Do these folks get up and dance around the room, looking for nulls and or lobes? I know I don't. I sit down with a refreshing drink, a book or tablet and........relax. If a symmetrical row of 2" Fullrange drivers with response from 500-5khz gets me there flanking a central line of ribbons, I ask 'why not?'.

for me, the ideal is 300 and 5000.
300-3000 was settled on by the phone company as ideal for their use, and 500-5000 was used for sound reinforcement. so i decided the ideal would be 300-5000.
i use that for my home system, but i dont think that its practical commercially